Sierra Space has secured a $798 million contract from the US Space Development Agency (SDA) to manufacture 18 advanced missile warning and tracking satellites for the Accelerated Missile Defense Tranche 3 (AMDT3) Tracking Layer. The satellites will be developed using Sierra Space’s Horizon spacecraft platform, a technology already being utilized under the company’s previous Tranche 2 Tracking Layer program. Under the earlier initiative, Sierra Space completed structural development for all 18 spacecraft and is preparing for qualification testing of a nine-satellite launch configuration, followed by full system verification activities. The new contract represents a significant expansion of Sierra Space’s role in the United States’ emerging Golden Dome missile defense architecture, which aims to establish a layered defense network combining orbital sensors, command-and-control systems, and interceptor technologies. The satellite constellation will provide continuous monitoring and tracking capabilities against advanced threats, including ballistic missiles, hypersonic weapons, and other maneuvering missile systems. Sierra Space CEO Dan Jablonsky highlighted that the company’s advanced manufacturing capabilities, integrated design approach, and industrial expertise allow it to deliver faster development timelines while reducing operational risks and costs. The AMDT3 program will operate alongside additional satellites developed by other defense contractors, including L3Harris Technologies, which has also received a contract for 18 missile defense satellites equipped with advanced tracking sensors. The Golden Dome initiative represents a major US investment in next-generation missile defense capabilities designed to protect the homeland across multiple phases of missile flight, including boost, midcourse, and glide phases. Recent investments have increased the program’s projected cost by billions of dollars as Washington accelerates development of space-based defense technologies. Major defense companies, including Lockheed Martin, RTX, and Northrop Grumman, are also participating in supporting future missile defense systems.
